Transco files report on 7-hour power outage in Mindanao on Easter Sunday

The National Transmission Corp. (Transco) has submitted to Energy Secretary Carlos Jericho L. Petilla a report on the seven-hour power shortage that hit Mindanao on Easter Sunday.

Petilla, who received the report the other day, said he has yet to review it. The energy chief formed a group to come up with a detailed report on the Mindanao-wide blackout.

“We sent the preliminary report to the Department of Energy [DOE] on Thursday,” Transco President Rolando Bacani said.

He said the main cause of the brownout was traced to a “corroded suspension insulator shank” that “gave way,” causing the “transmission line to fall and hitting the other line conductors and tower parts.”

This, he added, resulted in a short circuit “which was not isolated on time.”

The power outage started at 7:50 a.m. Power was restored after seven hours.

Bacani said Mindanao, particularly in Zamboanga, continues to experience limited power supply.

Mindanao’s gross power reserve on April 18 stands at 74 megawatts (MW); 134 MW on April 19; and
56 MW on April 20.

“In Mindanao there are areas having rotational brownouts due to power supply contracting deficiency by distribution utilities and low outputs from hydropower plants,” DOE Director Myleen Capongcol said in a text message.

Bacani added that Transco recommended an immediate inspection or a replacement of all suspension insulators in the area, considering that these were installed a long time ago and a thorough inspection was wanting.

“We also recommended the immediate review of the timing coordination of protective relays and the installation of new and back-up protection as the case may be. These are just some of the recommendations included in our report to the DOE,” the Transco official said.

Petilla also said his office would conduct an investigation involving Therma South Inc. (TSI), a subsidiary of AboitizPower, whose power facility in Davao City was damaged by the recent Mindanao-wide blackout.

The property damage will delay the commercial operations of Unit 2 by approximately 10 months, or until February 2016. Unit 1 and Unit 2 of the power plant have yet to be turned over to TSI by its contractors.

TSI was scheduled to synchronize Unit 2 with the Mindanao grid last week. Full commercial operations was supposed to happen a month after.

“My question to them is simple. Where is their circuit breaker? Why are they the only ones affected? They can say all they want but they are a party of interest. We will investigate this,” Petilla said.

When sought for comment, TSI President Benjie Cariaso Jr. said the company is also concerned about the incident. “We are also conducting our own investigation, assisted by a third-party consultant, to determine the root cause of the incident.”

The auxiliary components to the boiler of Unit 2 of TSI’s 300-MW coal power plant were damaged. Affected areas and components include the air-preheater, as well as the electrostatic precipitator, which is part of the power plant’s pollution-control system.

More than 20 distribution utilities and electric cooperatives have signed up to receive capacity from TSI.

The TSI official assured the public that the status of Unit 2 will not affect the commissioning of Unit 1, which remains on schedule and should reach commercial operation by the end of June this year.